Signaling of multiple short tti transmissions

ABSTRACT

Systems and methods are described herein for scheduling multiple short Transmission Time Internal (sTTI) transmissions. In some embodiments, a method of operation of a network node of a wireless communication network for scheduling multiple sTTI transmissions comprises transmitting a control information message to a wireless device for two or more sTTI transmissions, wherein the control information message comprises scheduling information indicating two or more scheduled sTTIs for the two or more sTTI transmissions, respectively, and/or an indication of a timing for the two or more scheduled sTTIs for the two or more sTTI transmissions and/or an indication of a Demodulation Reference Signal (DMRS) configuration for the two or more scheduled sTTIs for the two or more sTTI transmissions. By using multi-sTTI scheduling, control signaling overhead is reduced.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/495,723, filed Sep. 19, 2019, which is a 35 U.S.C. § 371 nationalphase application of International Application No. PCT/SE2018/050318,filed Mar. 26, 2018, the content of which is incorporated herein byreference in its entirety, which claims the benefit of U.S. ProvisionalApplication, Ser. No. 62/502,089, filed May 5, 2017, entitled SIGNALINGOF MULTIPLE SHORT TTI TRANSMISSIONS.

TECHNICAL FIELD

The present disclosure relates to scheduling short transmission timeinterval transmissions in a wireless communications network.

BACKGROUND I. Long Term Evolution (LTE) Frame Structure and PhysicalChannels for 1 Millisecond (Ms) Transmission Time Interval (TTI)

In Third Generation Partnership Project (3GPP) LTE systems, datatransmissions in both downlink (i.e., from a network node or enhanced orevolved Node B (eNB) to a user device or User Equipment device (UE)) anduplink (from a user device or UE to a network node or eNB) are organizedinto radio frames of 10 milliseconds (ms), each radio frame consistingof ten equally-sized subframes of length T_(subframe)=1 ms, as shown inFIG. 1.

LTE uses Orthogonal Frequency Division Multiplexing (OFDM) in thedownlink and Single Carrier OFDM (SC-OFDM) in the uplink. The basic LTEdownlink physical resource can thus be seen as a time-frequency grid asillustrated in FIG. 2, where each resource element corresponds to oneOFDM subcarrier during one OFDM symbol interval.

Furthermore, the resource allocation in LTE is typically described interms of Resource Blocks (RBs), where a RB corresponds to one slot (0.5ms) in the time domain and 12 contiguous subcarriers in the frequencydomain. RBs are numbered in the frequency domain, starting with 0 fromone end of the system bandwidth.

Similarly, the LTE uplink resource grid is illustrated in FIG. 3, whereN_(RB) ^(UL) is the number of RBs contained in the uplink systembandwidth, N_(sc) ^(RB) is the number subcarriers in each RB, typicallyN_(sc) ^(RB)=12, N_(symb) ^(UL) is the number of SC-OFDM symbols in eachslot. N_(symb) ^(UL)=7 for normal Cyclic Prefix (CP) and N_(symb)^(UL)=6 for extended CP. A subcarrier and a SC-OFDM symbol form anuplink Resource Element (RE).

Downlink data transmissions from an eNB to a UE are dynamicallyscheduled, i.e., in each subframe the base station transmits controlinformation about to which terminals data is transmitted and upon whichRBs the data is transmitted, in the current downlink subframe or thedownlink part (DwPTS) of the current special subframe. This controlsignaling is typically transmitted in the first 1, 2, 3, or 4 OFDMsymbols in each subframe. A downlink subframe with three OFDM symbols ascontrol is illustrated in FIG. 4.

Similar to downlink, uplink transmissions from a UE to an eNB are alsodynamically scheduled through the downlink control channel. When a UEreceives an uplink grant in subframe n, it transmits data in the uplinkat subframe n+k, where k=4 for a Frequency Division Duplexing (FDD)system and k varies for Time Division Duplexing (TDD) systems.

In LTE, several physical channels and signals are supported fortransmission of control information and data payloads. Some of thedownlink physical channels and signals supported in LTE are:

-   -   Physical Downlink Shared Channel (PDSCH)    -   Physical Downlink Control Channel (PDCCH)    -   Enhanced PDCCH (ePDCCH)    -   Reference signals:        -   Cell Specific Reference Signals (CRSs)        -   Demodulation Reference Signal (DMRS) for PDSCH        -   Channel State Information Reference Signals (CSI-RSs)

PDSCH is used mainly for carrying user traffic data and higher layermessages in the downlink and is transmitted in a downlink subframeoutside of the control region as shown in FIG. 4. Both PDCCH and ePDCCHare used to carry Downlink Control Information (DCI) such as Physical RB(PRB) allocation, Modulation and Coding Scheme (MCS), precoder used atthe transmitter, etc.

Existing physical layer downlink control channels, PDCCH and ePDCCH, aretransmitted once per 1 ms subframe. Furthermore, a PDCCH is distributedover the whole carrier bandwidth, but is time multiplexed with PDSCHover the first 1-4 symbols in the subframe. An ePDCCH is distributedover the whole 1 ms subframe, but is frequency multiplexed with PDSCHand multiplexed onto one or multiple PRB pairs for localized anddistributed transmission respectively. PDCCH has a common search spacewhere all UEs need to detect common cell specific control information.Depending whether the UE has been configured for ePDCCH or not, itsearches UE specific control information from UE search space of ePDCCHor PDCCH, respectively.

It is also noted that the size of the PDCCH region can changedynamically on subframe basis. Recall that the size of the PDCCH regionis signaled on the Physical Control Format Indicator Channel (PCFICH) inthe beginning of the 1 ms subframe. The frequency domain allocation ofthe ePDCCH is semi-statically configured by means of higher layersignaling.

Some of the uplink physical channels and signals supported in LTE are:

-   -   Physical Uplink Shared Channel (PUSCH)    -   Physical Uplink Control Channel (PUCCH)    -   DMRS for PUSCH    -   DMRS for PUCCH

The PUSCH is used to carry uplink data or/and uplink control informationfrom the UE to the eNB. The PUCCH is used to carry uplink controlinformation from the UE to the eNB.

II. DCI Formats for 1 ms TTI Scheduling

The current control channels carry control information, referred to asDCI. There are several DCI formats which have different optionsdepending on, e.g., configured transmission mode. The DCI format has aCyclic Redundancy Check (CRC) which is scrambled by a UE identifier,such as a Cell Radio Network Temporary Identifier (C-RNTI), and when theCRCs match, after descrambling, a PDCCH with a certain DCI format hasbeen detected. There are also identifiers that are shared by multipleterminals, such as the System Information Radio Network TemporaryIdentifier (SI-RNTI) which is used for transmission of systeminformation.

a. DCI Formats for Downlink Scheduling Assignments

There are currently a number of different DCI formats, see 3GPPTechnical Specification (TS) 36.212 for downlink resource assignmentsincluding formats 1, 1A, 1B, 1C, 1D, 2, 2A, 2B, 2C, and 2D.

Format 1: single codeword transmission

-   -   1 bit for indicating resource allocation type (type 0 or type 1)    -   ┌N_(RB) ^(DL)/P┐ bits for the resource allocation (type 0 or        type 1)    -   3 bits for Hybrid Automatic Repeat Request (HARQ) process number        (4 bits for TDD)    -   3 bits for New Data Indicator (NDI) and Redundancy Version (RV)    -   5 bits for MCS

Format 1A, 1B, 1D

-   -   ┌log₂ (N_(RB) ^(DL)(N_(RB) ^(DL)+1)/2) bits for the resource        allocation (type 2)    -   3 bits for HARQ process number (4 bits for TDD)    -   3 bits for NDI and RV    -   5 bits for MCS

Format 2, 2A, 2B, 2C, 2D: two codeword transmission

-   -   ┌N_(RB) ^(DL)/P┐ bits for the resource allocation (type 0 or        type 1)    -   3 bits for HARQ process number (4 bits for TDD)    -   2×3 bits for NDI and RV    -   2×5 bits for MCS        Here, P is the RB group size which depends on the system        bandwidth and N_(RB) ^(DL) is the number of RBs in the downlink.

The DCI for a downlink scheduling assignment hence contains informationon downlink data resource allocation in the frequency domain (theresource allocation), MCS, and HARQ process information. In case ofcarrier aggregation, information related to which carrier the PDSCH istransmitted on may be included as well.

b. DCI Formats for Uplink Scheduling Grants

There are two main families of DCI formats for uplink grants, DCI format0 and DCI format 4. The latter is added in Release 10 for supportinguplink spatial multiplexing. Several DCI format variants exist for bothDCI format 0 and DCI format 4 for various purposes, e.g. scheduling inunlicensed spectrum.

In general, the DCI for an uplink scheduling grant contains:

-   -   Resource allocation information        -   Carrier indicator        -   Resource allocation type        -   RB allocation    -   RS and data related information        -   MCS        -   NDI        -   Cyclic shift of the uplink DMRS        -   Precoding information        -   Transmit power control    -   Other information        -   Sounding Reference Signal (SRS) request        -   Channel State Information (CSI) request        -   Uplink index (for TDD)        -   DCI format 0/1A indication (only in DCI format 0 and 1A)        -   Padding        -   CRC scrambled with Radio Network Temporary Identifier (RNTI)            of the terminal            III. Latency Reduction with Short TTI (sTTI)

Packet data latency is one of the performance metrics that vendors,operators, and also end-users (via speed test applications) measureregularly. Latency measurements are done in all phases of a radio accessnetwork system lifetime, when verifying a new software release or systemcomponent, when deploying a system, and when the system is in commercialoperation.

Shorter latency than previous generations of 3GPP Radio AccessTechnologies (RATs) was one performance metric that guided the design ofLTE. The end-users also now recognize LTE to be a system that providesfaster access to the Internet and lower data latencies than previousgenerations of mobile radio technologies.

Packet data latency is important not only for the perceivedresponsiveness of the system; it is also a parameter that indirectlyinfluences the throughput of the system. Hypertext Transfer Protocol(HTTP)/Transmission Control Protocol (TCP) is the dominating applicationand transport layer protocol suite used on the Internet today. Accordingto HTTP Archive (http://httparchive.org/trends.php), the typical size ofHTTP based transactions over the Internet are in the range of a few tensof kilobytes up to one megabyte. In this size range, the TCP slow startperiod is a significant part of the total transport period of the packetstream. During TCP slow start the performance is latency limited. Hence,improved latency can rather easily be showed to improve the averagethroughput for this type of TCP based data transactions.

Latency reductions could positively impact radio resource efficiency.Lower packet data latency could increase the number of transmissionspossible within a certain delay bound; hence higher Block Error Rate(BLER) targets could be used for the data transmissions freeing up radioresources potentially improving the capacity of the system.

One approach to latency reduction is the reduction of transport time ofdata and control signaling by addressing the length of a TTI. Byreducing the length of a TTI and maintaining the bandwidth, theprocessing time at the transmitter and the receiver nodes is alsoexpected to be reduced, due to less data to process within the TTI. InLTE Release 8, a TTI corresponds to one subframe of length 1 ms. Onesuch 1 ms TTI is constructed by using 14 OFDM or SingleCarrier-Frequency Division Multiple Access (SC-FDMA) symbols in the caseof normal CP and 12 OFDM or SC-FDMA symbols in the case of extended CP.In LTE Release 14, a study item on latency reduction has been conducted,with the goal of specifying transmissions with shorter TTIs, such as aslot or a few symbols [3GPP TR 36.881]. A work item with the goal ofspecifying sTTI started in August 2016 [3GPP RP-162014].

a. Reduced Processing Time for Shorter TTI

In LTE, a minimum required processing time is specified and applied forthe downlink HARQ feedback timing and the uplink grant to uplink datadelay. The latter is also called uplink scheduling timing. In case ofsTTI, the minimum processing time will be reduced. For 2 OFDM symbol(2os) TTI, the minimum required processing timing could be k−1 sTTI,resulting in a timing of n+k. An example is k=6 sTTI. This means that aUE receiving a downlink assignment for a downlink sTTI received indownlink sTTI n is expected to transmit the downlink HARQ feedback inuplink sTTI n+k. The same can be applied for the uplink schedulingtiming. A UE receiving an uplink grant for an uplink sTTI in downlinksTTI n is expected to transmit the uplink data in uplink sTTI n+k.

In TDD, the sTTI n+k may not be a valid uplink sTTI, in which casespecial rules for the timing can be defined but the minimum processingtiming cannot be earlier than n+k. Similarly, in case of differentdownlink and uplink TTI lengths (for instance 2os TTI in downlink andslot TTI in uplink), the timing n+k may not always correspond to a validsTTI in uplink, in which case special rules can be defined, such as HARQfeedback or uplink data should be sent in the earliest uplink sTTI aftern+k.

b. sTTI Configuration in a Subframe

An sTTI can be decided to have any duration in time and compriseresources on a number of OFDM or SC-FDMA symbols within a 1 ms subframe.As one example shown in FIG. 5, the duration of the uplink sTTI is 0.5ms, i.e. seven SC-FDMA symbols for the case with normal CP. As anotherexample shown in FIG. 6, the durations of the uplink sTTIs within asubframe are of 2 or 3 symbols. Here, the “R” in the figures indicatesthe DMRS symbols, and “S” indicates the SRS symbols.

For uplink sTTI transmissions, shorter TTI lengths lead to larger DMRSoverhead assuming at least one SC-FDMA symbol for transmitting DMRSwithin each sTTI for channel estimation. For very short TTI lengths,e.g. 2-symbol sTTI, the DMRS overhead can be 50%, leading to asignificant performance loss in terms of throughput and spectralefficiency. In LTE, different DMRS design options have been consideredto reduce the DMRS overhead:

-   -   DMRS multiplexing: In case different UEs are scheduled in        consecutive sTTIs, multiple UEs share the same SC-FMDA symbol        for transmitting DMRS sequences, but having separate SC-FMDA        symbols for the data.    -   DMRS sharing: When the same UE is scheduled on consecutive        sTTIs, the DMRS is not transmitted in each sTTI. Instead, the        DMRS transmitted in the first sTTI will be shared by the        following scheduled sTTIs for channel estimation.

Example mechanisms depicted in FIG. 7 and FIG. 8 would work both forDMRS sharing and DMRS multiplexing. For DMRS multiplexing, consider theexample of UE 1 scheduled in sTTI 0 and UE 2 in sTTI 1. In FIG. 7, UE 1will transmit data in SC-FDMA symbols 0 and 1 and DMRS in symbol 2. UE 2will transmit DMRS in the same symbol and data in symbols 3 and 4. Ifthe mechanism depicted in FIG. 8 is used, UE 1 will transmit DMRS insymbol 0 and data in symbols 1 and 2. UE 2 will transmit DMRS in symbol0, be silent in symbols 1 and 2, and send data in symbols 3 and 4.

In case of DMRS sharing, UE 1 is scheduled in both sTTI 0 and sTTI 1. InFIG. 7, UE 1 transmits data in symbols 0, 1, 3, and 4 and DMRS in symbol2. In FIG. 8, UE 1 transmits data in symbols 1, 2, 3, and 4 and DMRS insymbol 0.

FIG. 9 shows examples for 2 or 3-symbol downlink sTTI configurationswithin a subframe. Downlink transmissions can be CRS based or DMRSbased. For DMRS based transmissions, the DMRS sharing option, asexplained for uplink, can also be used for downlink sTTI transmissionsto reduce the DMRS overhead.

Throughout this disclosure, short PDSCH (sPDCCH) and short PUSCH(sPUSCH) to denote the downlink and uplink physical shared channels withsTTIs, respectively. Similarly, short PDCCH (sPDCCH) is used to denotedownlink physical control channels with sTTIs.

c. Downlink and Uplink sTTI Scheduling

To schedule an uplink or a downlink sTTI transmission, it is possiblefor the eNB to transmit the corresponding control information by using anew DCI format, referred to as short DCI (sDCI), in each downlink sTTI.The control channel carrying this sDCI can be either PDCCH or sPDCCH.

SUMMARY

Systems and methods are described herein for scheduling multiple shortTransmit Time Internal (sTTI) transmissions. In some embodiments, amethod of operation of a network node of a wireless communicationnetwork for scheduling multiple sTTI transmissions comprisestransmitting a control information message to a wireless device for twoor more sTTI transmissions, wherein the control information messagecomprises scheduling information indicating two or more scheduled sTTIsfor the two or more scheduled sTTI transmissions, respectively, and/oran indication of a timing for the two or more scheduled sTTIs for thetwo or more scheduled sTTI transmissions and/or an indication of a DMRSconfiguration for the two or more scheduled sTTIs for the two or morescheduled sTTI transmissions. By using multi-sTTI scheduling, controlsignaling overhead is reduced.

In some embodiments, the two or more sTTI transmissions comprise two ormore uplink sTTI transmissions. In some other embodiments, the two ormore sTTI transmissions comprise two or more downlink sTTItransmissions.

In some embodiments, the two or more scheduled sTTIs are consecutive inthe time domain.

In some embodiments, the control information message is transmitted on aphysical downlink control channel. In some other embodiments, thecontrol information message is transmitted on a short physical downlinkcontrol channel used for scheduling sTTI transmissions. In some otherembodiments, the control information message can be transmitted oneither a physical downlink control channel or a short physical downlinkcontrol channel used for scheduling both uplink and downlink sTTItransmissions. In some embodiments, a short physical downlink controlchannel can be transmitted in each downlink sTTI, except for a legacycontrol region.

In some embodiments, the control information message comprises a bitfield that indicates the number of scheduled sTTIs. In some embodiments,the two or more scheduled sTTIs are determined by a fixed schedulingtiming and the bit field of the control information message thatindicates the number of scheduled sTTIs. In some embodiments, aplurality of possible combinations of two or more sTTI transmissions arepredefined, and the bit field comprised in the control informationmessage together with an index of a downlink sTTI containing the controlmessage explicitly indicates one of the plurality of possiblecombinations of two or more sTTI transmissions as a selected combinationof sTTIs for the sTTI transmissions. Further, in some embodiments, thecontrol information message is comprised in a short physical downlinkcontrol channel. In some other embodiments, a plurality of possiblecombinations of two or more sTTI transmissions are predefined, and thebit field comprised in the control information message explicitlyindicates one of the plurality of possible combinations of two or moresTTI transmissions as a selected combination of sTTIs for the sTTItransmissions. Further, in some embodiments, the control informationmessage is comprised in a physical downlink control channel for a TTIthat comprises a plurality of sTTIs.

In some embodiments, a DMRS configuration for each of the plurality ofpossible combinations of two or more sTTI transmissions ispreconfigured. In some other embodiments, the control informationcomprises a second bit field that indicates a DMRS configuration for thetwo or more scheduled sTTI transmissions. In some other embodiments, thecontrol information comprises a second bit field that, together with thenumber of scheduled sTTIs, indicates a DMRS configuration for the two ormore scheduled sTTI transmissions. In some embodiments, the DRMSconfiguration comprises a number of DMRS symbols and/or DMRS symbolpositions for the two or more scheduled sTTIs.

In some embodiments, the control information message comprises a firstbit field that indicates the number of scheduled sTTIs and a second bitfield that indicates a timing of at least a first scheduled sTTI of thetwo or more sTTIs, and the two or more scheduled sTTIs are determined bythe first bit field of the control information message that indicatesthe number of scheduled sTTIs and the second bit field of the controlinformation message that indicates the timing of at least the firstscheduled sTTI.

In some embodiments, the scheduling information is slot-based multi-sTTIscheduling information that schedules all sTTIs in one or more slots asthe two or more scheduled sTTIs. In some embodiments, transmission ofthe control information message is limited to PDCCH. In someembodiments, transmission of the control information message is limitedto PDCCH and a first sTTI in a second slot of the subframe.

In some embodiments, a DMRS configuration, including both a number ofDMRS symbols and DMRS symbol positions, is preconfigured or configuredby signaling, for each of a plurality of possible combinations of two ormore scheduled sTTIs.

In some embodiments, a DMRS configuration for the scheduled sTTIs,including both a number of DMRS symbols and DMRS symbol positions, isdetermined by a separate bit field of the control information message.

Embodiments of a network node are also disclosed. In some embodiments, anetwork node for a wireless communication network for schedulingmultiple sTTI transmissions is adapted to perform the method of any oneof the embodiments of a method of operation of a network node describedherein.

In some embodiments, a network node for a wireless communication networkfor scheduling multiple sTTI transmissions comprises at least oneprocessor and memory storing instructions executable by the at least oneprocessor whereby the network node is operable to perform the method ofany one of the embodiments of a method of operation of a network nodedescribed herein.

Embodiments of a method of operation of a wireless device are alsodisclosed. In some embodiments, a method of operation of a wirelessdevice in a wireless communication network comprises receiving, from anetwork node, a control information message for two or more sTTItransmissions, wherein the control information message comprisesscheduling information indicating two or more scheduled sTTI for the twoor more scheduled sTTI transmissions, respectively, and/or an indicationof a timing for the two or more scheduled sTTIs for the two or morescheduled sTTI transmissions and/or an indication of a DMRSconfiguration for the two or more scheduled sTTIs for the two or morescheduled sTTI transmissions. The method further comprises transmittingand/or receiving the two or more sTTI transmissions in accordance withthe control information message.

In some embodiments, the control information message comprises a bitfield that indicates the number of scheduled sTTIs. Further, in someembodiments, the two or more scheduled sTTIs are determined by a fixedscheduling timing and the bit field of the control information messagethat indicates the number of scheduled sTTIs. In some embodiments, aplurality of possible combinations of two or more sTTI transmissions arepredefined, and the bit field comprised in the control informationmessage together with an index of a downlink sTTI containing the controlmessage explicitly indicates one of the plurality of possiblecombinations of two or more sTTI transmissions as a selected combinationof sTTIs for the sTTI transmissions. Further, in some embodiments, thecontrol information message is comprised in a short physical downlinkcontrol channel. In some other embodiments, a plurality of possiblecombinations of two or more sTTI transmissions are predefined, and thebit field comprised in the control information message explicitlyindicates one of the plurality of possible combinations of two or moresTTI transmissions as a selected combination of sTTIs for the sTTItransmissions. Further, in some embodiments, the control informationmessage is comprised in a physical downlink control channel for a TTIthat comprises a plurality of sTTIs.

In some embodiments, a DMRS configuration for each of the plurality ofpossible combinations of two or more sTTI transmissions ispreconfigured. In some other embodiments, the control informationcomprises a second bit field that indicates a DMRS configuration for thetwo or more scheduled sTTI transmissions. In some other embodiments, thecontrol information comprises a second bit field that, together with thenumber of scheduled sTTIs, indicates a DMRS configuration for the two ormore scheduled sTTI transmissions. In some embodiments, the DRMSconfiguration comprises a number of DMRS symbols and/or DMRS symbolpositions for the two or more scheduled sTTIs.

In some embodiments, the control information message comprises a firstbit field that indicates the number of scheduled sTTIs and a second bitfield that indicates a timing of at least a first scheduled sTTI of thetwo or more sTTIs, and the two or more scheduled sTTIs are determined bythe first bit field of the control information message that indicatesthe number of scheduled sTTIs and the second bit field of the controlinformation message that indicates the timing of at least the firstscheduled sTTI.

In some embodiments, the scheduling information is slot-based multi-sTTIscheduling information that schedules all sTTIs in one or more slots asthe two or more scheduled sTTIs.

In some embodiments, transmission of the control information message islimited to PDCCH. In some other embodiments, transmission of the controlinformation message is limited to PDCCH and a first sTTI in a secondslot of the subframe.

In some embodiments, a DMRS configuration, including both a number ofDMRS symbols and DMRS symbol positions, is preconfigured or configuredby signaling, for each of a plurality of possible combinations of two ormore scheduled sTTIs.

In some embodiments, a DMRS configuration for the scheduled sTTIs,including both a number of DMRS symbols and DMRS symbol positions, isdetermined by a separate bit field of the control information message.

Embodiments of a wireless device are also disclosed. In someembodiments, a wireless device for a wireless communication network isadapted to perform the method of operation of a wireless device inaccordance with any one of the embodiments of the method of operation ofa wireless device disclosed herein.

In some embodiments, a wireless device for a wireless communicationnetwork comprises at least one transceiver and circuitry associated withthe at least one transceiver, the circuitry operable to receive, from anetwork node via the at least one transceiver, a control informationmessage for one or more sTTI transmissions, wherein the controlinformation message comprises scheduling information indicating one ormore scheduled sTTI for the one or more scheduled sTTI transmissions,respectively, and/or an indication of a timing for the one or morescheduled sTTIs for the one or more scheduled sTTI transmissions and/oran indication of a DMRS configuration for the one or more scheduledsTTIs for the one or more scheduled sTTI transmissions. The circuitry isfurther operable to transmit and/or receive, via the at least onetransceiver, the one or more sTTI transmissions in accordance with thecontrol information message.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the disclosure, andtogether with the description serve to explain the principles of thedisclosure.

FIG. 1 illustrates an LTE time-domain structure;

FIG. 2 illustrates an LTE downlink physical resource;

FIG. 3 illustrates an LTE uplink resource grid;

FIG. 4 illustrates an LTE downlink subframe;

FIG. 5 illustrates an example of 7-symbol sTTI configuration with anuplink subframe;

FIG. 6 illustrates an example of a 2/3 symbol sTTI configuration with anuplink subframe;

FIG. 7 illustrates an example of 2/3 symbol sTTI configuration with DMRSmultiplexing/sharing;

FIG. 8 illustrates an example of a 2/3 symbol sTTI configuration withinan uplink subframe with DMRS multiplexing/sharing;

FIG. 9 illustrates examples of a 2/3 symbol sTTI configuration within adownlink subframe;

FIG. 10 illustrates one example of a wireless communication system inwhich embodiments of the present disclosure may be implemented;

FIG. 11 illustrates the operation of a radio access node and a wirelessdevice according to some embodiments of the present disclosure;

FIG. 12 is an illustration of n+6 uplink scheduling timing for 2/3symbol sTTI configurations in both uplink and downlink where sDCI can betransmitted in each downlink sTTI according to some embodiments of thepresent disclosure;

FIG. 13 illustrates an example of using 1 bit in the sDCI for indicatingthe DMRS configuration of the scheduled multiple sTTIs according to someembodiments of the present disclosure;

FIG. 14 illustrates an example of n+6 uplink scheduling timing for 2/3symbol sTTI configurations in both uplink and downlink where sDCI formulti-sTTI scheduling can only be transmitted from PDCCH;

FIG. 15 illustrates an example of n+4 uplink scheduling timing for 2/3symbol sTTI configurations in both uplink and downlink. Multi-sTTI DCIcan only be transmitted from PDCCH according to some embodiments of thepresent disclosure;

FIGS. 16 and 17 illustrate example embodiments of a wireless device; and

FIGS. 18 through 20 illustrate example embodiments of a network node(e.g., a radio access node).

DETAILED DESCRIPTION

The embodiments set forth below represent information to enable thoseskilled in the art to practice the embodiments and illustrate the bestmode of practicing the embodiments. Upon reading the followingdescription in light of the accompanying drawing figures, those skilledin the art will understand the concepts of the disclosure and willrecognize applications of these concepts not particularly addressedherein. It should be understood that these concepts and applicationsfall within the scope of the disclosure.

Radio Node: As used herein, a “radio node” is either a radio access nodeor a wireless device.

Radio Access Node: As used herein, a “radio access node” or “radionetwork node” is any node in a radio access network of a cellularcommunications network that operates to wirelessly transmit and/orreceive signals. Some examples of a radio access node include, but arenot limited to, a base station (e.g., a New Radio (NR) base station(gNB) in a 3GPP Fifth Generation (5G) NR network or an eNB in a 3GPP LTEnetwork), a high-power or macro base station, a low-power base station(e.g., a micro base station, a pico base station, a home eNB, or thelike), and a relay node.

Core Network Node: As used herein, a “core network node” is any type ofnode in a core network. Some examples of a core network node include,e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway(P-GW), a Service Capability Exposure Function (SCEF), or the like.

Wireless Device: As used herein, a “wireless device” is any type ofdevice that has access to (i.e., is served by) a cellular communicationsnetwork by wirelessly transmitting and/or receiving signals to a radioaccess node(s). Some examples of a wireless device include, but are notlimited to, a UE in a 3GPP network and a Machine Type Communication(MTC) device.

Network Node: As used herein, a “network node” is any node that iseither part of the radio access network or the core network of acellular communications network/system.

Short Transmission Time Interval (sTTI): As used herein, a “sTTI” is atransmission duration that is shorter than a nominal transmissionduration. In LTE, the nominal transmission duration is called a subframeand is composed of 14 OFDM/SC-FDMA symbols with normal cyclic prefix. InLTE, a 2 or 3 OFDM symbol long transmission can also be referred to assubslot transmission, while a 7 OFDM symbol long transmission can alsobe referred to as slot transmission. In NR, the nominal transmissionduration is called a slot and is composed of 14 OFDM/SC-FDMA symbolswith normal cyclic prefix. In NR, a transmission duration of less than14 OFDM symbols can also be referred to as PDSCH/PUSCH type B(mini-slot/non-slot based transmission) in NR.

Note that the description given herein focuses on a 3GPP cellularcommunications system and, as such, 3GPP terminology or terminologysimilar to 3GPP terminology is oftentimes used. However, the conceptsdisclosed herein are not limited to a 3GPP system.

Note that, in the description herein, reference may be made to the term“cell;” however, particularly with respect to 5G NR concepts, beams maybe used instead of cells and, as such, it is important to note that theconcepts described herein are equally applicable to both cells andbeams.

Using existing technology, in order to schedule an uplink or a downlinksTTI transmission, the eNB transmits corresponding control informationusing a new DCI format, referred to as short DCI (sDCI), in eachdownlink sTTI. The control channel carrying this sDCI can be eitherPDCCH or sPDCCH. However, transmitting sDCI in every single sTTIrepresents a high control overhead, especially for 2/3-symbol sTTI. Thismeans that the number of available REs to be used for data transmissionis reduced due to the RE utilized for the sDCI transmissions. Thisoverhead can be seen as unnecessary when a UE is scheduled inconsecutive sTTIs within a 1 ms subframe under similar channelconditions.

For DMRS sharing, a UE is scheduled with multiple consecutive sTTIs, andthe DMRS is only transmitted in the first sTTI to reduce the overhead.If an sDCI is intended for scheduling only a single sTTI transmission,then multiple scheduling assignments/grants should be sent forscheduling these consecutive sTTIs. This will increase the controlsignaling overhead.

In addition, it can cause a reliability issue for DMRS sharing. Forexample, consider the uplink DMRS sharing case, where the UE misses thefirst uplink grant, so it will not transmit DMRS. Then, the eNB will notbe able to decode the following sTTI transmissions due to lack ofchannel information.

Different signaling methods for multi-sTTI scheduling for both uplinkand downlink sTTI transmissions are disclosed herein. Embodiments of thepresent disclosure support the scheduling of multiple sTTI transmissionsfor both downlink and uplink transmissions—CRS based for downlink andDMRS based for downlink and uplink—to reduce both the DMRS overheadbased on DMRS sharing and control signaling overhead from the sDCItransmissions. In addition, embodiments of the present disclosureprovide the same reliability for DMRS sharing as for the single sTTItransmission for downlink and uplink.

FIG. 10 illustrates one example of a wireless communication network 10(e.g., an LTE (e.g., LTE Advanced (LTE-A), LTE-Pro, or an enhancedversion of LTE) or 5G NR network) in which embodiments of the presentdisclosure may be implemented. As illustrated, a number of wirelessdevices 12 (e.g., UEs) wirelessly transmit signals to and receivesignals from radio access nodes 14 (e.g., eNBs or gNBs, which is a 5G NRbase station), each serving one or more cells 16. The radio access nodes14 are connected to a core network 18.

FIG. 11 illustrates the operation of the radio access node 14 and thewireless device 12 according to some embodiments of the presentdisclosure. In general, this process is performed by the radio accessnode 14 (or more generally a network node) to provide scheduling ofmultiple sTTI transmissions in uplink and/or downlink. As illustrated,the radio access node 14 transmits a control information message to thewireless device 12 (step 100). The control information message is forone or more scheduled sTTI transmissions, which may be uplinktransmissions or downlink transmissions. The control information messageincludes scheduling information that indicates the sTTI(s) for thescheduled sTTI transmission(s) and/or an indication of a timing for thescheduled sTTI transmission(s) and/or an indication of a DMRSconfiguration for the scheduled sTTI transmission(s). Further, asdiscussed below, in some embodiments, the control information message isfor two or more scheduled sTTI transmissions, e.g., in two or moreconsecutive sTTIs in the time domain.

In some embodiments, the control information message includes schedulinginformation that indicates the sTTI(s) for the scheduled sTTItransmission(s), where the scheduling information is uplink schedulinginformation and/or downlink scheduling information. In other words, thescheduled sTTI transmission(s) are uplink transmission(s) or downlinktransmission(s). In some embodiments, the control information includesscheduling information that indicates two or more sTTIs for two or moresTTI transmissions, respectively, where the two or more sTTIs areconsecutive in the time domain.

In some embodiments, the control information message is referred to assDCI, and the sDCI can be transmitted from in both PDCCH and sPDCCH.Here, a sPDCCH is used for scheduling both uplink and downlink sTTItransmissions. A sPDCCH can be transmitted in each downlink sTTI, exceptfor the legacy control region. Further, in some embodiments, the sTTIsfor the scheduled sTTI transmissions (sometimes referred to herein asscheduled sTTIs) are determined by a fixed scheduling timing and a bitfield of the sDCI indicating the number of scheduled sTTIs.

In some embodiments, a DMRS configuration, including both the number ofDMRS symbols and the position of the DMRS symbols, is preconfigured orconfigured by signaling (e.g., Radio Resource Control (RRC) signaling),for each possible combination of multiple scheduled sTTIs. In some otherembodiments, the DMRS configuration for the scheduled sTTIs, includingboth the number of DMRS symbols and the position of the DMRS symbols, isindicated in the sDCI (e.g., indicated by a separate bit field of thesDCI).

In some embodiments, the control information message (for two or morescheduled sTTI transmissions scheduled on two or more sTTIsrespectively) is transmitted only once per subframe. Further, in someembodiments, the control information message is carried only on PDCCH.

In some embodiments, the control information message is transmitted onlyonce per slot. For instance, it is carried on PDCCH for the first slotin the subframe, and on the first sPDCCH of the second slot in thesubframe. Further, in some embodiments, the possible combinations ofmultiple scheduled sTTIs are predefined, and a bit field of the sDCItogether with a fixed scheduling timing are used to explicitly indicatethe selected combination of sTTIs for multi-sTTI transmissions.

In some embodiments, the scheduled sTTIs are determined by a bit fieldof the sDCI indicating the number of scheduled sTTIs together with a bitfield of the sDCI indicating the timing of at least the first scheduledsTTI.

Upon receiving the control information message, the wireless device 12receives (or downlink embodiments) or transmits (for uplink embodiments)the scheduled sTTI transmissions in accordance with the controlinformation message (step 102). In other words, the wireless device 12performs data decoding (downlink) or data transmission (uplink) based onthe received control information message.

In the following, some examples are provided for how to signal multiplescheduled sTTI transmissions in both uplink and downlink.

In a first embodiment, the control information message, which isreferred to as sDCI, can be transmitted from each downlink sTTI. Asignaling example is presented below, assuming only consecutive sTTIscan be scheduled, and the maximum number of scheduling sTTIs is three.However, since this is only an example, the present disclosure is notlimited thereto.

FIG. 12 shows the earliest uplink sTTI that can be scheduled from anuplink grant sent in a downlink sTTI considering the n+6 uplinkscheduling timing for 2 or 3-symbol sTTI transmissions. For instance,assuming that there are 6 sTTIs per subframe, if an uplink grant is sentin downlink sTTI 0 in subframe n, this grant can schedule uplink sTTI 0in subframe n+1 at the earliest. If the uplink grant is a multi-sTTIscheduling grant sent in downlink sTTI 0 in subframe n, this grant couldschedule uplink sTTI 0 and uplink sTTI 1 in subframe n+1 for instance(but not earlier than uplink sTTI 0 in subframe n+1).

Considering the n+6 uplink scheduling timing for 2 or 3-symbol sTTItransmissions shown in FIG. 12, Table 1 gives the mapping of the valueof the 1-bit field in the sDCI to the scheduled multiple consecutivesTTIs.

TABLE 1 An example of using 1 bit in the sDCI for uplink multi-sTTIscheduling with n + 6 scheduling timing DL index Scheduled UL sTTI index(sDCI) on bit field Number On subframe On subframe subframe (n)Nrof_sTTI of sTTIs (n + 1) (n + 2) 0 0 2 0 and 1 — 0 1 3 0 and 1 and 2 —1 0 2 1 and 2 — 1 1 3 1 and 2 and 3 — 2 0 2 2 and 3 — 2 1 3 2 and 3 and4 — 3 0 2 3 and 4 — 3 1 3 3 and 4 and 5 — 4 0 2 4 and 5 — 4 1 3 4 and 50 5 0 2 5 - 0 5 1 3 5  0 and 1

For downlink scheduling, the same approach can be applied, except thatthe scheduled downlink sTTI does not have the n+6 scheduling timingconstraint. Instead, the downlink scheduling timing can be down to n+0,meaning that the earliest downlink sTTI that can be scheduled by adownlink assignment found in downlink sTTI n is downlink sTTI n. Table1A gives the mapping of the value of the 1-bit field in the sDCI to thescheduled multiple consecutive sTTIs.

TABLE 1A An example of using 1 bit in the sDCI for downlink multi-sTTIscheduling with n + 0 scheduling timing DL index Scheduled DL sTTI index(sDCI) on bit field Number On subframe On subframe subframe (n)Nrof_sTTI of sTTIs (n) (n + 1) 0 0 2 0 and 1 — 0 1 3 0 and 1 and 2 — 1 02 1 and 2 — 1 1 3 1 and 2 and 3 — 2 0 2 2 and 3 — 2 1 3 2 and 3 and 4 —3 0 2 3 and 4 — 3 1 3 3 and 4 and 5 — 4 0 2 4 and 5 — 4 1 3 4 and 5 0 50 2 5 - 0 5 1 3 5  0 and 1

The DMRS configuration for each scheduled multi-sTTI combination can bepreconfigured for both uplink transmissions and DMRS-based downlinktransmissions. For example, for uplink multi-sTTI scheduling, the DMRSis always placed at the first SC-FDMA symbol of the first scheduleduplink sTTI. As another example, for downlink multi-sTTI scheduling, theDMRS is always placed at the first OFDM symbol of the first scheduleddownlink sTTI. It is also possible to re-configure the DMRS position byRRC signaling to adapt the channel conditions.

Another way is to use a separate bit field in the sDCI for indicatingthe DMRS configuration, so that the DMRS configuration can dynamicallyadapt to the channel conditions. FIG. 13 illustrates an example of howto use 1 bit in the sDCI for indicating the DMRS configuration for somemulti-sTTI combinations in uplink.

In the downlink, there should always be DMRS symbols in the first sTTIof the series of sTTIs scheduled with multi-sTTI scheduling. Thisenables the UE to start decoding the first sTTI of the series before theother sTTIs, as in case of single sTTI scheduling, and send thecorresponding downlink HARQ feedback after the predefined downlink HARQfeedback delay. A dynamic DMRS configuration can allow changing theperiodicity of the DMRS insertion in the series of scheduled sTTIsstarting from the first sTTI. For instance, if the field for DMRSconfiguration is set to 0, only the first sTTI of the series ofscheduled sTTIs contains DMRS. If the field is set to 1, every secondsTTI of the series contains DMRS, starting from the first sTTI.

In the downlink, the DMRS configuration field can also have a differentinterpretation depending on the number of scheduled sTTIs in the series.For instance, if the field for DMRS configuration is set to 0 and thenumber of scheduled sTTI in the series is less than the number of sTTIsin a subframe, only the first sTTI of the series of scheduled sTTIscontains DMRS. If the field for DMRS configuration is set to 0 and thenumber of scheduled sTTI in the series equals the number of sTTIs of asubframe (i.e. 6 sTTIs for LTE 2os TTI), the first sTTI of each LTE slotcontains DMRS. If the field is set to 1, every second sTTI of the seriescontains DMRS, starting from the first sTTI.

In a second embodiment, sDCI for multi-sTTI scheduling can only betransmitted from PDCCH. In other words, in order to reduce the signalingoverhead and the blind decoding complexity at the UE (e.g., the wirelessdevice 12), it can be restricted that the sDCI for multi-sTTIscheduling, defined as multi-sTTI DCI, is only transmitted from PDCCH.In the following, two signaling examples are given, assuming that onlyconsecutive sTTIs can be scheduled in the multi-sTTI DCI. However, sincethis is only an example, the present disclosure is not limited thereto.

Given this method, the UE (e.g., the wireless device 12) monitors themulti-sTTI DCI in PDCCH only. Consequently, the UE does not expect DCIfor multi-sTTI scheduling on sPDCCH. But, it does monitor both singleand multi-sTTI DC's in PDCCH. Additionally, if a multi-sTTI schedulingfor downlink/uplink assignment is found in PDCCH, the UE would not needto search for an sDCI in the already scheduled sTTIs. For the sTTIswhich are not scheduled by the multi-sTTI DCI transmitted in PDCCH, theUE should monitor sDCI.

In a first variation of the second embodiment, a single bit field isincluded in the control information for indicating the scheduled sTTIs.Considering the n+6 uplink scheduling timing for 2 or 3-symbol sTTItransmissions shown in FIG. 14, Table 2 lists all the possiblecombinations of multiple consecutive sTTIs that can be scheduled bysending a multi-sTTI DCI from the PDCCH. It can be seen that 4 bits aresufficient for indicating all possible combinations for the uplink ordownlink multi-sTTI scheduling. Note that in this case, the downlinksTTIs belong to the same subframe where the multi-sTTI DCI istransmitted, while uplink sTTIs are in the next subframe.

The same method can be used for other uplink scheduling timing as well.For example, as shown in FIG. 15 and Table 3, considering the n+4scheduling timing, it is also possible to use 4 bits to indicate thescheduled multiple sTTIs. Note that in this case, the sTTI 4 and sTTI 5are in the same subframe where the multi-sTTI DCI is transmitted, whilesTTI 0, 1, 2, and 3 are in the next subframe.

TABLE 2 A bit field of sDCI for uplink multi-sTTI scheduling with n + 6scheduling timing or downlink multi- sTTI with n + 0 scheduling timing.bit field Scheduled UL/DL sTTI index 0 0 0 0 0 and 1 0 0 0 1 1 and 2 0 01 0 2 and 3 0 0 1 1 3 and 4 0 1 0 0 4 and 5 0 1 0 1 0 and 1 and 2 0 1 10 1 and 2 and 3 0 1 1 1 2 and 3 and 4 1 0 0 0 3 and 4 and 5 1 0 0 1 0and 1 and 2 and 3 1 0 1 0 1 and 2 and 3 and 4 1 0 1 1 2 and 3 and 4 and5 1 1 0 0 0 and 1 and 2 and 3 and 4 1 1 0 1 1 and 2 and 3 and 4 and 5 11 1 0 0 and 1 and 2 and 3 and 4 and 5 1 1 1 1 reserved

TABLE 3 A bit field of sDCI for uplink multi-sTTI scheduling with n + 4scheduling timing bit field Scheduled UL sTTI index 0 0 0 0 4 and 5 0 00 1 5 and 0 0 0 1 0 0 and 1 0 0 1 1 1 and 2 0 1 0 0 2 and 3 0 1 0 1 4and 5 and 0 0 1 1 0 5 and 0 and 1 0 1 1 1 0 and 1 and 2 1 0 0 0 1 and 2and 3 1 0 0 1 4 and 5 and 0 and 1 1 0 1 0 5 and 0 and 1 and 2 1 0 1 1 0and 1 and 2 and 3 1 1 0 0 4 and 5 and 0 and 1 and 2 1 1 0 1 5 and 0 and1 and 2 and 3 1 1 1 0 4 and 5 and 0 and 1 and 2 and 3 1 1 1 1 reserved

In practice, not all these 15 combinations shown in Table 1 and Table 2are needed. For example, to keep good channel estimation performance,the maximum number of consecutive sTTIs that is allowed can be limitedto 3. In this case, only 3 bits are needed for the signaling. It is alsopossible to reduce the signaling overhead by removing some combinations,e.g., the ones that all scheduled sTTIs are not within the samesubframe, or not within the same slot.

As an enhancement of the described method, the reserved combination(e.g., 1111) can be reused to convey signaling for a single sTTIscheduling. Thereby, the eNB can schedule either single or multiple sTTIusing same multi-sTTI DCI format in PDCCH. Given that, the UE maymonitor only multi-sTTI (downlink and uplink) DCIs on PDCCH. Forinstance, if the bit field is set to 1111 in downlink multi-sTTI DCI,the scheduled downlink sTTI index is 0. if the bit field is set to 1111in uplink multi-sTTI DCI, the scheduled uplink sTTI index is 4 in samesubframe or 0 in next subframe for n+4 and n+6 uplink scheduling timing,respectively. The methods on DMRS configuration discussed above withrespect to method 1 apply for method 2 as well. For the sTTIs which arenot scheduled by the multi-sTTI DCI transmitted in PDCCH, the UE shouldmonitor sDCI.

In a second variation of the second embodiment, two different bit fieldsare included in the control information and used to indicate thescheduled sTTIs. In other words, another method for signaling thescheduled multiple sTTIs is by using two separate bit fields, one forindicating the timing, i.e., n+k+Δ_(I), of the first scheduled sTTI, andthe other field for indicating the number of the scheduling sTTIs. Table4 illustrates an example of using this signaling method, assuming n+6minimum scheduling timing. Note that in this case, the downlink sTTIsbelong to the same subframe where the multi-sTTI DCI is transmitted,while uplink sTTI are in the next subframe.

Similarly, the number of required signaling bits can be reduced byremoving some combinations.

TABLE 4 An example of using two different bit fields of the sDCI foruplink and downlink multi-sTTI scheduling with n + k + ΔI schedulingtiming and k = 6 Scheduled Bit field for Bit field Number Timing UL/DLNumber_of_sTTI for timing of sTTIs offset, ΔI sTTI index 0 0 0 0 0 0 2 00 and 1 0 0 0 0 0 1 2 1 1 and 2 0 0 0 0 1 0 2 2 2 and 3 0 0 0 0 1 1 2 33 and 4 0 0 0 1 0 0 2 4 4 and 5 0 0 1 0 0 0 3 0 0 and 1 and 2 0 0 1 0 01 3 1 1 and 2 and 3 0 0 1 0 1 0 3 2 2 and 3 and 4 0 0 1 0 1 1 3 3 3 and4 and 5 0 1 0 0 0 0 4 0 0 and 1 and 2 and 3 0 1 0 0 0 1 4 1 1 and 2 and3 and 4 0 1 0 0 1 0 4 2 2 and 3 and 4 and 5 0 1 1 0 0 0 5 0 0 and 1 and2 and 3 and 4 0 1 1 0 0 1 5 1 1 and 2 and 3 and 4 and 5 1 0 0 0 0 0 6 00 and 1 and 2 and 3 and 4 and 5 others others reserved reserved reserved

Similar to the enhancement in the first variation of the secondembodiment, single sTTI scheduling can be supported by the multi-sTTIDCI. The UE may monitor only multi-sTTI (downlink/uplink) DCI in PDCCH.For the sTTIs which are not scheduled by the multi-sTTI DCI transmittedin PDCCH, the UE should monitor sDCI.

In a third embodiment, slot-based multi-sTTI scheduling DCI is provided.The third embodiment allows scheduling a minimum of one complete slot.The third embodiment can be seen as a subset of the first and secondembodiments. Using slot-based multi-sTTI DCI, the eNB can schedule allsTTIs in the first slot, all sTTIs in the second slot, or all sTTIs inboth slots. Table 5 shows an example.

Multi-sTTI DCI can be limited to PDCCH or additionally to the first sTTIin the second slot of the subframe.

In case of six sTTIs per subframe and an uplink scheduling timing ofn+6, the third embodiment is well suited for scheduling multiple uplinksTTIs of a slot from the first downlink sTTI of a slot. The thirdembodiment can however also be applied in case that the uplinkscheduling timing k in n+k does not correspond to the number of sTTIsper subframe, p (i.e., p is not equal to k). In that case, twoalternatives exist. In the first alternative, a rule is defined for theUEs so that a multi-sTTI uplink grant received in a downlink sTTI nindicates scheduling of sTTIs of slots starting at the earliest at orafter the uplink scheduling timing n+k. In the second alternative, aTiming offset, Δ_(I) can be signaled in the uplink multi-sTTI DCI toadjust the timing of the sTTI scheduled to start from the next possibleslot after n+k.

TABLE 5 An example of using slot based scheduling sDCI for uplink anddownlink multi-sTTI scheduling with respectively n + 6 and n + 0scheduling timing. Scheduled Scheduled DL sTTI UL sTTI sDCI in slotindex in slot index index on on on on on subframe subframe subframesubframe subframe (n) Bit field (n) (n + 1) (n + 1) (n + 2) 0 00 0 — 0 —0 01 1 — 1 — 0 10 0 and 1 — 0 and 1 — 0 Reserved Reserved ReservedReserved Reserved 3 00 1 — 1 — 3 01 — 0 — 0 3 10 1 0 1 0 3 ReservedReserved Reserved Reserved Reserved

Single sTTI scheduling can be supported by the multi-sTTI DCI by reusingthe reserved combination. So that the UE may monitor only multi-sTTI(downlink/uplink) DCI in PDCCH and the first sTTI of the second slot.For the sTTIs within each slot which are not scheduled by the respectivemulti-sTTI DCI, the UE should monitor sDCI.

Other aspects of the present disclosure relating to multi-sTTI DCI willnow be described. To limit the number of additional bits in the DCI formulti-sTTI scheduling, i.e. multi-sTTI DCI, restrictions such as sameMCS, Precoding Matrix Indicator (PMI), and resource allocation are validoptions. Those fields are not expected to change significantly withinconsecutive sTTIs. The following fields are not extended per sTTI;instead, the same value is applied for all scheduled sTTIs:

-   -   Resource allocation header (resource allocation type 0/type 1)    -   Resource block assignment    -   TCP command for PUCCH    -   Downlink assignment index    -   HARQ process number    -   MCS/TB    -   Precoding information depending on TM

On the other hand, RV and NDI fields should be specified per sTTI toenable multiplexing of new data and retransmissions on different sTTIsusing one DCI. Thereby, the length of NDI field is equivalent to theconfigured maximum number of sTTI scheduled by DCI for multi-sTTIscheduling.

As for the HARQ Identifier (ID) number, the DCI for the multi-subframescheduling includes the HARQ process number for the first subframe (i)in the scheduled burst. The HARQ process number for the remainingsubframe in (i+1, . . . N−1) are decided based on the followingequation:

mod(n _(HARQ_ID) +i,N _(HARQ))

-   -   the value of n_(HARQ_ID) is determined by the HARQ process        number field in the corresponding DCI format    -   the value of N_(HARQ) is the number of configured HARQ        processes.    -   the value of N is determined by the number of scheduled sTTI in        the corresponding DCI format.

FIG. 16 is a schematic block diagram of the wireless device 12 (e.g.,UE) according to some embodiments of the present disclosure. Asillustrated, the wireless device 12 includes circuitry 20 comprising oneor more processors 22 (e.g., Central Processing Units (CPUs),Application Specific Integrated Circuits (ASICs), Field ProgrammableGate Arrays (FPGAs), Digital Signal Processors (DSPs), and/or the like)and memory 24. The wireless device 12 also includes one or moretransceivers 26 each including one or more transmitters 28 and one ormore receivers 30 coupled to one or more antennas 32. In someembodiments, the functionality of the wireless device 12 (e.g., thefunctionality of a UE) described herein may be implemented in hardware(e.g., via hardware within the circuitry 20 and/or within theprocessor(s) 22) or be implemented in a combination of hardware andsoftware (e.g., fully or partially implemented in software that is,e.g., stored in the memory 24 and executed by the processor(s) 22).

In some embodiments, a computer program including instructions which,when executed by the at least one processor 22, causes the at least oneprocessor 22 to carry out at least some of the functionality of thewireless device 12 (e.g., the functionality of a UE) according to any ofthe embodiments described herein is provided. In some embodiments, acarrier containing the aforementioned computer program product isprovided. The carrier is one of an electronic signal, an optical signal,a radio signal, or a computer readable storage medium (e.g., anon-transitory computer readable medium such as memory).

FIG. 17 is a schematic block diagram of the wireless device 12 (e.g.,UE) according to some other embodiments of the present disclosure. Thewireless device 12 includes one or more modules 34, each of which isimplemented in software. The module(s) 34 provide the functionality ofthe wireless device 12 described herein. For example, the modules(s) 34may include a receiving/transmitting module operable to perform thefunction of step 102 of FIG. 11.

FIG. 18 is a schematic block diagram of a network node 36 (e.g., a radioaccess node 14 such as, for example, an eNB or gNB) or a core networknode according to some embodiments of the present disclosure. Asillustrated, the network node 36 includes a control system 38 thatincludes circuitry comprising one or more processors 40 (e.g., CPUs,ASICs, DSPs, FPGAs, and/or the like) and memory 42. The control system38 also includes a network interface 44. In embodiments in which thenetwork node 36 is a radio access node 14, the network node 36 alsoincludes one or more radio units 46 that each include one or moretransmitters 48 and one or more receivers 50 coupled to one or moreantennas 52. In some embodiments, the functionality of the network node36 (specifically the functionality of the radio access node 14 or eNB)described above may be fully or partially implemented in software thatis, e.g., stored in the memory 42 and executed by the processor(s) 40.

FIG. 19 is a schematic block diagram that illustrates a virtualizedembodiment of the network node 36 (e.g., the radio access node 14 or acore network node) according to some embodiments of the presentdisclosure. As used herein, a “virtualized” network node 36 is a networknode 36 in which at least a portion of the functionality of the networknode 36 is implemented as a virtual component (e.g., via a virtualmachine(s) executing on a physical processing node(s) in a network(s)).As illustrated, the network node 36 optionally includes the controlsystem 38, as described with respect to FIG. 18. In addition, if thenetwork node 36 is the radio access node 14, the network node 36 alsoincludes the one or more radio units 46, as described with respect toFIG. 18. The control system 38 (if present) is connected to one or moreprocessing nodes 54 coupled to or included as part of a network(s) 56via the network interface 44. Alternatively, if the control system 38 isnot present, the one or more radio units 46 (if present) are connectedto the one or more processing nodes 54 via a network interface(s).Alternatively, all of the functionality of the network node 36 (e.g.,all of the functionality of the radio access node 14 or eNB) describedherein may be implemented in the processing nodes 54. Each processingnode 54 includes one or more processors 58 (e.g., CPUs, ASICs, DSPs,FPGAs, and/or the like), memory 60, and a network interface 62.

In this example, functions 64 of the network node 36 (e.g., thefunctions of the radio access node 14 or eNB) described herein areimplemented at the one or more processing nodes 54 or distributed acrossthe control system 38 (if present) and the one or more processing nodes54 in any desired manner. In some particular embodiments, some or all ofthe functions 64 of the network node 36 described herein are implementedas virtual components executed by one or more virtual machinesimplemented in a virtual environment(s) hosted by the processing node(s)54. As will be appreciated by one of ordinary skill in the art,additional signaling or communication between the processing node(s) 54and the control system 38 (if present) or alternatively the radiounit(s) 46 (if present) is used in order to carry out at least some ofthe desired functions. Notably, in some embodiments, the control system38 may not be included, in which case the radio unit(s) 46 (if present)communicates directly with the processing node(s) 54 via an appropriatenetwork interface(s).

In some particular embodiments, higher layer functionality (e.g., layer3 and up and possibly some of layer 2 of the protocol stack) of thenetwork node 36 may be implemented at the processing node(s) 54 asvirtual components (i.e., implemented “in the cloud”) whereas lowerlayer functionality (e.g., layer 1 and possibly some of layer 2 of theprotocol stack) may be implemented in the radio unit(s) 46 and possiblythe control system 38.

In some embodiments, a computer program including instructions which,when executed by the at least one processor 40, 58, causes the at leastone processor 40, 58 to carry out the functionality of the network node36 or a processing node 54 according to any of the embodiments describedherein is provided. In some embodiments, a carrier containing theaforementioned computer program product is provided. The carrier is oneof an electronic signal, an optical signal, a radio signal, or acomputer readable storage medium (e.g., a non-transitory computerreadable medium such as the memory 60).

FIG. 20 is a schematic block diagram of the network node 36 (e.g., theradio access node 14 or a core network node) according to some otherembodiments of the present disclosure. The network node 36 includes oneor more modules 66, each of which is implemented in software. Themodule(s) 66 provide the functionality of the network node 36 describedherein. In some embodiments, the module(s) 66 comprise, for example, atransmitting module operable to transmit the control information messageas described above, e.g., with respect to step 100 of FIG. 11.

While not being limited thereto, some example embodiments of the presentdisclosure are provided below.

Embodiment 1: A method of operation of a network node (14) of a wirelesscommunication network (10) for scheduling multiple sTTI transmissions,comprising: transmitting (100) a control information message to awireless device (12) for one or more sTTI transmissions; wherein thecontrol information message comprises scheduling information indicatingone or more scheduled sTTI for the one or more scheduled sTTItransmissions, respectively, and/or an indication of a timing for theone or more scheduled sTTIs for the one or more scheduled sTTItransmissions and/or an indication of a DMRS configuration for the oneor more scheduled sTTIs for the one or more scheduled sTTItransmissions.

Embodiment 2: The method of embodiment 1 wherein the one or more sTTItransmissions comprise one or more uplink sTTI transmissions and/or oneor more downlink sTTI transmissions.

Embodiment 3: The method of embodiment 1 or 2 wherein the one or moresTTI transmissions comprise two or more sTTI transmissions scheduled fortwo or more sTTIs, respectively.

Embodiment 4: The method of embodiment 3 wherein the two or morescheduled sTTIs are consecutive in the time domain.

Embodiment 5: The method of any one of embodiments 1 to 4 wherein thecontrol information message is transmitted on a physical downlinkcontrol channel.

Embodiment 6: The method of any one of embodiments 1 to 4 wherein thecontrol information message is transmitted on a short physical downlinkcontrol channel used for scheduling sTTI transmissions.

Embodiment 7: The method of any one of embodiments 1 to 4 wherein thecontrol information message can be transmitted on either a physicaldownlink control channel or a short physical downlink control channelused for scheduling both uplink and downlink sTTI transmissions.

Embodiment 8: The method of embodiment 6 or 7 wherein a short physicaldownlink control channel can be transmitted in each downlink sTTI,except for a legacy control region.

Embodiment 9: The method of any one of embodiments 1 to 8 wherein thecontrol information message comprises a bit field that indicates thenumber of scheduled sTTIs, and the scheduled sTTIs are determined by afixed scheduling timing and the bit field of the control informationmessage that indicates the number of scheduled sTTIs.

Embodiment 10: The method of any one of embodiments 1 to 8 wherein: theone or more scheduled sTTI transmissions comprise two or more sTTItransmissions scheduled on two or more scheduled sTTIs, respectively; aplurality of possible combinations of two or more sTTI transmissions arepredefined; and a bit field of the control information message togetherwith a fixed scheduling timing are used to explicitly indicate aselected combination of sTTIs for the sTTI transmissions.

Embodiment 11: The method of any one of embodiments 1 to 8 wherein thecontrol information message comprises a first bit field that indicatesthe number of scheduled sTTIs and a second bit field that indicates atiming of at least a first scheduled sTTI of the one or more sTTIs, andthe scheduled sTTIs are determined by the first bit field of the controlinformation message that indicates the number of scheduled sTTIs and thesecond bit field of the control information message that indicates thetiming of at least the first scheduled sTTI.

Embodiment 12: The method of any one of embodiments 1 to 11 wherein theone or more scheduled sTTI transmissions comprise two or more sTTItransmissions scheduled on two or more scheduled sTTIs, respectively,and a DMRS configuration, including both a number of DMRS symbols andDMRS symbol positions, is preconfigured or configured by signaling, foreach possible combination of two or more scheduled sTTIs.

Embodiment 13: The method of any one of embodiments 1 to 11 wherein theone or more scheduled sTTI transmissions comprise two or more sTTItransmissions scheduled on two or more scheduled sTTIs, respectively,and a DMRS configuration for the scheduled sTTIs, including both anumber of DMRS symbols and DMRS symbol positions, is determined by aseparate bit field of the control information message.

Embodiment 14: The method of any one of embodiments 1 to 13 wherein thecontrol information message is transmitted only once per subframe, andit is carried only on PDCCH.

Embodiment 15: The method of any one of embodiments 1 to 13 wherein thecontrol information message is transmitted only once per slot (e.g., itis carried on PDCCH for the first slot in the subframe, and on the firstshort PDCCH of the second slot in the subframe).

Embodiment 16: A network node (14) for a wireless communication network(10) for scheduling multiple sTTI transmissions, the network node (14)adapted to perform the method of any one of embodiments 1 to 15.

Embodiment 17: A network node (14) for a wireless communication network(10) for scheduling multiple sTTI transmissions, comprising: at leastone processor (40, 58); and memory (42, 60) storing instructionsexecutable by the at least one processor (40, 58) whereby the networknode (14) is operable to perform the method of any one of embodiments 1to 15.

Embodiment 18: A network node (14) for a wireless communication network(10) for scheduling multiple sTTI transmissions, comprising: one or moremodules (66) operable to perform the method of any one of embodiments 1to 15.

Embodiment 19: A computer program comprising instructions which, whenexecuted on at least one processor, cause the at least one processor tocarry out the method according to any one of embodiments 1 to 15.

Embodiment 20: A carrier containing the computer program of embodiment19, wherein the carrier is one of an electronic signal, an opticalsignal, a radio signal, or a computer readable storage medium.

Embodiment 21: A method of operation of a wireless device (12) in awireless communication network (10), comprising: receiving (100), from anetwork node (14), a control information message for one or more sTTItransmissions, wherein the control information message comprisesscheduling information indicating one or more scheduled sTTI for the oneor more scheduled sTTI transmissions, respectively, and/or an indicationof a timing for the one or more scheduled sTTIs for the one or morescheduled sTTI transmissions and/or an indication of a DMRSconfiguration for the one or more scheduled sTTIs for the one or morescheduled sTTI transmissions; and transmitting and/or receiving (102)the one or more sTTI transmissions in accordance with the controlinformation message.

Embodiment 22: A wireless device (12) for a wireless communicationnetwork (10), the wireless device (12) adapted to perform the method ofembodiment 21.

Embodiment 23: A wireless device (12) for a wireless communicationnetwork (10), comprising: at least one transceiver (26); and circuitry(20) associated with the at least one transceiver (26), the circuitry(20) operable to: receive, from a network node (14) via the at least onetransceiver (26), a control information message for one or more sTTItransmissions, wherein the control information message comprisesscheduling information indicating one or more scheduled sTTI for the oneor more scheduled sTTI transmissions, respectively, and/or an indicationof a timing for the one or more scheduled sTTIs for the one or morescheduled sTTI transmissions and/or an indication of a DMRSconfiguration for the one or more scheduled sTTIs for the one or morescheduled sTTI transmissions; and transmit and/or receive, via the atleast one transceiver (26), the one or more sTTI transmissions inaccordance with the control information message.

Embodiment 24: A wireless device (12) for a wireless communicationnetwork (10), comprising: a receiving module (34) operable to receive,from a network node (14), a control information message for one or moresTTI transmissions, wherein the control information message comprisesscheduling information indicating one or more scheduled sTTI for the oneor more scheduled sTTI transmissions, respectively, and/or an indicationof a timing for the one or more scheduled sTTIs for the one or morescheduled sTTI transmissions and/or an indication of a DMRSconfiguration for the one or more scheduled sTTIs for the one or morescheduled sTTI transmissions; and a transmitting/receiving module (34)operable to transmit and/or receive the one or more sTTI transmissionsin accordance with the control information message.

Embodiment 25: A computer program comprising instructions which, whenexecuted on at least one processor, cause the at least one processor tocarry out the method according to embodiment 21.

Embodiment 26: A carrier containing the computer program of embodiment25, wherein the carrier is one of an electronic signal, an opticalsignal, a radio signal, or a computer readable storage medium.

The following acronyms are used throughout this disclosure.

3GPP Third Generation Partnership Project 5G Fifth Generation ASICApplication Specific Integrated Circuit BLER Block Error Rate CP CyclicPrefix CPU Central Processing Unit CRC Cyclic Redundancy Check C-RNTICell Radio Network Temporary Identifier CRS Cell Specific ReferenceSignal CSI Channel State Information CSI-RS Channel State InformationReference Signals DCI Downlink Control Information DMRS DemodulationReference Signal DSP Digital Signal Processor eNB Enhanced or EvolvedNode B ePDCCH enhanced Physical Downlink Control Channel FDD FrequencyDivision Duplexing FPGA Field Programmable Gate Array gNB New Radio BaseStation HARQ Hybrid Automatic Repeat Request HTTP Hypertext TransferProtocol ID Identifier LTE Long Term Evolution LTE-A Long Term EvolutionAdvanced MCS Modulation and Coding Scheme MME Mobility Management Entityms Millisecond MTC Machine Type Communication NDI New Data IndicatorOFDM Orthogonal Frequency Division Multiplexing PCFICH Physical ControlFormat Indicator Channel PDCCH Physical Downlink Control Channel PDSCHPhysical Downlink Shared Channel P-GW Packet Data Network Gateway PMIPrecoding Matrix Indicator PRB Physical Resource Block PUCCH PhysicalUplink Control Channel PUSCH Physical Uplink Shared Channel RAT RadioAccess Technology RB Resource Block RE Resource Element RNTI RadioNetwork Temporary Identifier RRC Radio Resource Control RV RedundancyVersion sDCI Short Downlink Control Information SCEF Service CapabilityExposure Function SC-FDMA Single Carrier-Frequency Division MultipleAccess SC-OFDM Single Carrier-Orthogonal Frequency Division MultiplexingSI-RNTI System Information Radio Network Temporary Identifier sPDCCHShort Physical Downlink Control Channel sPDSCH Short Physical DownlinkShared Channel sPUSCH Short Physical Uplink Shared Channel SRS SoundingReference Signal sTTI Short Transmission Time Interval TCP TransmissionControl Protocol TDD Time Division Duplexing TS Technical SpecificationTTI Transmission Time Interval UE User Equipment

Those skilled in the art will recognize improvements and modificationsto the embodiments of the present disclosure. All such improvements andmodifications are considered within the scope of the concepts disclosedherein.

1-51. (canceled)
 52. A method of operation of a network node of awireless communication network for scheduling multiple shortTransmission Time Interval, sTTI, transmissions, comprising:transmitting a control information message to a wireless device for twoor more sTTI transmissions; wherein the control information messagecomprises: downlink scheduling information indicating two or morescheduled downlink sTTIs for the two or more sTTI transmissions, thedownlink scheduling information including an indication of a timing forthe two or more scheduled downlink sTTIs for the two or more sTTItransmissions and an indication of a number of the scheduled downlinksTTIs; and optionally uplink scheduling information indicating two ormore scheduled uplink sTTIs for the two or more sTTI transmissions, theuplink scheduling information including either one or both of: anindication of a timing for the two or more scheduled uplink sTTIs forthe two or more sTTI transmissions; and an indication of a DemodulationReference Signal, DMRS, configuration for the two or more scheduleduplink sTTIs for the two or more sTTI transmissions.
 53. The method ofclaim 52 wherein the two or more scheduled downlink sTTIs areconsecutive in the time domain, and optionally wherein the two or morescheduled uplink sTTIs are consecutive in the time domain.
 54. Themethod of claim 52 wherein the control information message istransmitted on either a physical downlink control channel or a shortphysical downlink control channel.
 55. The method of claim 54 wherein ashort physical downlink control channel is transmitted in each downlinksTTI transmission, except for a legacy control region.
 56. The method ofclaim 52 wherein the control information message comprises a bit fieldthat indicates the number of scheduled downlink sTTIs.
 57. The method ofclaim 56 wherein the two or more scheduled downlink sTTIs are determinedby a fixed scheduling timing and the bit field of the controlinformation message that indicates the number of scheduled downlinksTTIs.
 58. The method of claim 56 wherein: a plurality of possiblecombinations of two or more downlink sTTIs are predefined; and the bitfield comprised in the control information message together with anindex of a downlink sTTI transmission containing the control informationmessage explicitly indicates one of the plurality of possiblecombinations of two or more downlink sTTIs as a selected combination ofdownlink sTTIs for the two or more sTTI transmissions.
 59. The method ofclaim 58 wherein any one of: a Demodulation Reference Signal, DMRS,configuration for each of the plurality of possible combinations of twoor more sTTI transmissions is preconfigured; the control informationmessage comprises a second bit field that indicates a DemodulationReference Signal, DMRS, configuration for the two or more sTTItransmissions; and the control information message comprises a secondbit field that, together with the number of scheduled sTTIs, indicates aDMRS configuration for the two or more sTTI transmissions.
 60. Themethod of claim 59 wherein the DRMS configuration comprises either oneor both of: a number of DMRS symbols for the two or more scheduledsTTIs; and a number of DMRS symbol positions for the two or morescheduled sTTIs.
 61. The method of claim 56 wherein: a plurality ofpossible combinations of two or more downlink sTTIs are predefined; andthe bit field comprised in the control information message explicitlyindicates one of the plurality of possible combinations of two or moredownlink sTTIs as a selected combination of downlink sTTIs for the twoor more sTTI transmissions and, optionally, wherein the controlinformation message is comprised in a physical downlink control channelfor a Transmission Time Interval, TTI, that comprises a plurality ofsTTIs.
 62. The method of claim 61 wherein any one of: a DemodulationReference Signal, DMRS, configuration for each of the plurality ofpossible combinations of two or more sTTI transmissions ispreconfigured; the control information message comprises a second bitfield that indicates a Demodulation Reference Signal, DMRS,configuration for the two or more sTTI transmissions; and the controlinformation message comprises a second bit field that, together with thenumber of scheduled sTTIs, indicates a DMRS configuration for the two ormore sTTI transmissions.
 63. The method of claim 62 wherein the DRMSconfiguration comprises either one or both of: a number of DMRS symbolsfor the two or more scheduled sTTIs; and a number of DMRS symbolpositions for the two or more scheduled sTTIs.
 64. A network node for awireless communication network for scheduling multiple shortTransmission Time Interval, sTTI, transmissions, comprising: at leastone processor; and memory storing instructions executable by the atleast one processor whereby the network node is operable to perform amethod for scheduling multiple short Transmission Time Interval, sTTI,transmissions, comprising: transmitting a control information message toa wireless device for two or more sTTI transmissions; wherein thecontrol information message comprises: downlink scheduling informationindicating two or more scheduled downlink sTTIs for the two or more sTTItransmissions, the downlink scheduling information including anindication of a timing for the two or more scheduled downlink sTTIs forthe two or more sTTI transmissions and an indication of a number of thescheduled downlink sTTIs; and optionally uplink scheduling informationindicating two or more scheduled uplink sTTIs for the two or more sTTItransmissions, the uplink scheduling information including either one orboth of: an indication of a timing for the two or more scheduled uplinksTTIs for the two or more sTTI transmissions; and an indication of aDemodulation Reference Signal, DMRS, configuration for the two or morescheduled uplink sTTIs for the two or more sTTI transmissions.
 65. Amethod of operation of a wireless device in a wireless communicationnetwork, comprising: receiving, from a network node, a controlinformation message for two or more short Transmission Time Interval,sTTI, transmissions, wherein the control information message comprises:downlink scheduling information indicating two or more scheduleddownlink sTTIs for the two or more sTTI transmissions, the downlinkscheduling information including an indication of a timing for the twoor more scheduled downlink sTTIs for the two or more sTTI transmissionsand an indication of a number of the scheduled downlink sTTIs; andoptionally uplink scheduling information indicating two or morescheduled uplink sTTIs for the two or more sTTI transmissions, theuplink scheduling information including either one or both of anindication of a timing for the two or more scheduled uplink sTTIs forthe two or more sTTI transmissions; and an indication of a DemodulationReference Signal, DMRS, configuration for the two or more scheduleduplink sTTIs for the two or more sTTI transmissions; and transmittingand/or receiving the two or more sTTI transmissions in accordance withthe control information message.
 66. A wireless device for a wirelesscommunication network, comprising: at least one transceiver; andcircuitry associated with the at least one transceiver, the circuitryoperable to: receive, from a network node via the at least onetransceiver, a control information message for one or more shortTransmission Time Interval, sTTI, transmissions, wherein the controlinformation message comprises: downlink scheduling informationindicating one or more scheduled downlink sTTI for the one or more sTTItransmissions, the downlink scheduling information including anindication of a timing for the two or more scheduled downlink sTTIs forthe two or more sTTI transmissions and an indication of a number ofscheduled downlink sTTIs; and optionally uplink scheduling informationindicating two or more scheduled uplink sTTIs for the two or more sTTItransmissions, the uplink scheduling information including either one orboth of an indication of a timing for the two or more scheduled uplinksTTIs for the two or more sTTI transmissions; and an indication of aDemodulation Reference Signal, DMRS, configuration for the two or morescheduled uplink sTTIs for the two or more sTTI transmissions; andtransmit and/or receive, via the at least one transceiver, the one ormore sTTI transmissions in accordance with the control informationmessage.
 67. A non-transitory computer readable medium storing computerprogram instructions which, when executed on at least one processor,cause the at least one processor to carry out a method for schedulingmultiple short Transmission Time Interval, sTTI, transmissions,comprising: transmitting a control information message to a wirelessdevice for two or more sTTI transmissions; wherein the controlinformation message comprises: downlink scheduling informationindicating two or more scheduled downlink sTTIs for the two or more sTTItransmissions, the downlink scheduling information including anindication of a timing for the two or more scheduled downlink sTTIs forthe two or more sTTI transmissions and an indication of a number of thescheduled downlink sTTIs; and optionally uplink scheduling informationindicating two or more scheduled uplink sTTIs for the two or more sTTItransmissions, the uplink scheduling information including either one orboth of: an indication of a timing for the two or more scheduled uplinksTTIs for the two or more sTTI transmissions; and an indication of aDemodulation Reference Signal, DMRS, configuration for the two or morescheduled uplink sTTIs for the two or more sTTI transmissions.